1. Field of the Invention
This invention pertains generally to telephone systems having means of registering numbers called and cost rates for the numbers called, retaining this data in a memory, timing the length of completed calls, and computing the actual cost of completed outgoing telephone calls. It is a user-oriented, small portable device designated to monitor the cost of the customer's telephone calls on a continuous basis. The device utilizes a microcomputer based calculator, programmable memory, keyboard data entry, continuous digital display, a continuous clock and a pickup coil to sense signals on a telephone line. In particular, this invention pertains to a consumer device which enables the consumer to monitor accurately the cost of his out-going telephone calls as those calls are in progress. As a consumer device, it is extremely simple to use.
2. Description of the Prior Art
Since the beginning of telephone service, telephone companies have developed and used equipment to monitor customer use of telephone service and to compute the customer's bill by calculating the length of time of the call multiplied by the rate in effect at the time of the call plus the applicable tax. The customer, or consumer, of telephone service has no way of knowing what his telephone bill will be until he actually receives it, except for the basic monthly rate he pays for telephone service (which may or may not include a limited number of local calls). Since telephone usage is to a great extent discretionary, the consumer should have a simple and reliable means of knowing the cost of the service as he uses it rather than wait a month to find out that he has overspent his budget. The rate schedules and tariffs published by telephone companies are of limited value and barely intelligible to the average cost conscious consumer, and of no value to those who lack computational skills. The device of the present invention is intended to be a portable simple, inexpensive means for the average consumer of telephone service to monitor the actual cost of the outgoing telephone calls he makes.
The prior patent art in cost computation systems for telephone calls is primarily oriented to central billing systems for telephone companies and operators of private branch exchanges. In a search of the prior patent art the applicant could find only two patents relevant to the disclosure of this invention. (U.S. Pat. No. 3,508,392 utilizes an old technology and is obsolete by current standards).
U.S. Pat. No. 4,065,640, issued to Rouiller, and U.S. Pat. No. 4,041,291, issued to Pavda, are the closest patents to the present invention which the applicant could find. Both of these patents depend upon the telephone company supplying coded electrical information for their automatic operation. This is not currently supplied by the telephone companies and there is no indication that it will be supplied in the near future. U.S. Pat. No. 4,041,291 teaches a small, portable instrument for simultaneously timing, computing and calculating the cost plus tax of a running long distance telephone toll call in dollars and cents and displaying its results on a screen. As such, the disclosure of this patent is very close to that of the present application. However, the device disclosed in that patent has many deficiencies which effectively serve to defeat its purpose. Its prime deficiency is that it requires the entry of telephone numbers and tariffs to be used each time a call is made, making it both difficult and time consuming for the average consumer to use. The procedural program of the device of this patent is using what should be fixed or stored data as variable data to be entered repetitively. The system program reverses the logic and rationale of a digital device and makes it both more complicated to use and more expensive to manufacture.
The device of the present invention uses a more conventional program logic to achieve the same goal while resulting in a device which is far simpler for the consumer to use and understand. It is also more easily expandable to more sophisticated and intensive uses such as those in a small business or a private PBX. For the purpose of this discussion, we shall ignore local message unit service or measured service since it accounts for only a small portion of the variable factor in the consumer's monthly telephone bill. It should be clearly understood, however, that the system of the present invention can easily handle such service in the same way that it handles long distance toll call service.
Experience has shown that the largest single cost variable in the average consumer's telephone bill is the long distance toll call. Furthermore, most long distance toll calls represent controllable, discretionary expenditures, either for the call itself or the length of time the call takes. Additionally, the average consumer calls only a few long distance numbers with any degree of regularity which would affect his cost. These would be the numbers of friends, relatives, business associates, customers, and the like. Thus, for the average consumer, only about twenty to fifty long distance telephone numbers are called with any degree of regularity that would significantly impact his costs. Another factor that affects the consumer's cost is that there are two basic rate structures in effect for long distance toll calls, one rate structure for interstate calls and one for intrastate calls.
The object of the present invention is to provide the consumer, especially the unsophisticated consumer, with a very simple and very inexpensive device to monitor the cost of his discretionary out-going long distance phone calls as these calls are in progress. Simplicity of use and low cost are achieved by providing a device which can be preprogrammed (by a third party, if necessary) to meet the needs of the individual consumer, by providing only the minimal memory to meet these needs, and by requiring the consumer to activate only a start key at the beginning of a call and a stop key at the end of the call.
The call cost monitor of the present invention is in effect a small, self-contained portable programmable computer which provides a means for the telephone utility consumer to monitor automatically the cost of at least a limited number of his long distance telephone toll calls. The cost is displayed on a digital display and updated each minute while the call is in progress. The call cost monitor functions independently of the telephone and thus is not dependent upon an interconnection into the telephone line for its operation. Its operating mode is automatic and it does not require that the telephone company supply coded pulse information identifying the cost of each toll call dialed. When not in use as a call cost monitor, it can continuously display the time of day.